1,720,989 research outputs found
Development of a time-effective and highly specific quantitative real-time polymerase chain reaction assay for the identification of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus in artisanal raw cow’s milk cheese
No full textThe first objective of this work included the development of real-time polymerase chain reaction (RT-PCR) which is also known as quantitative polymerase chain reaction (qPCR) assays to quantify two species of lactic acid bacteria which play a very important role in cheese ripening: Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus. The second objective was the comparison of qPCR and plate counts of these two species present in raw cow’s milk cheese samples during different stages of ripening. Thirty-three deoxyribonucleic acid (DNA) samples coming from seven different bacterial species, which were phylogenetically related or commonly isolated from raw milk and dairy products, were chosen as positive and negative controls. The qPCR assays showed a high quantification capacity characterised by their linearity (R2 > 0.998), PCR efficiencies which were within the range 78.0-90.0% for L. delbrueckii subsp. bulgaricus, and 93.6-100.5% for S. thermophilus, and quantification limit (103 gene copies/ml for L. delbrueckii subsp. bulgaricus and 10 gene copies/ml for S. thermophilus). The importance of our study is in the monitoring of changes in populations of L. delbrueckii subsp. bulgaricus and S. thermophilus contributing to cheese ripening using the newly designed qPCR assay
Current knowledge on interspecific hybrid palm oils as food and food ingredient
Full text linkThe consumers' opinion concerning conventional palm (Elaeis guineensis) oil is negatively affected by environmental and nutritional issues. However, oils extracted from drupes of interspecific hybrids Elaeis oleifera × E. guineensis are getting more and more interest, due to their chemical and nutritional properties. Unsaturated fatty acids (oleic and linoleic) are the most abundant constituents (60%-80% of total fatty acids) of hybrid palm oil (HPO) and are mainly acylated in position sn-2 of the glycerol backbone. Carotenes and tocotrienols are the most interesting components of the unsaponifiable matter, even if their amount in crude oils varies greatly. The Codex Committee on Fats and Oils recently provided HPO the "dignity" of codified fat substance for human consumption and defined the physical and chemical parameters for genuine crude oils. However, only few researches have been conducted to date on the functional and technological properties of HPO, thus limiting its utilization in food industry. Recent studies on the nutritional effects of HPO softened the initial enthusiasm about the "tropical equivalent of olive oil", suggesting that the overconsumption of HPO in the most-consumed processed foods should be carefully monitored
Brewing quality of hop varieties cultivated in central Italy based on multivolatile fingerprinting and bitter acid content
Full text linkThe brewing value of hops is mainly affected by the content and composition of humulones (α-acids) and essential oil. Interest in hop plantations is increasing more and more in Italy, in parallel with the rising number of microbreweries and brewpubs, which are strongly oriented towards local production chains. In this context, a selection of 15 international hop varieties were grown, under the same conditions, in an experimental field in the Marche region, Central Italy, with the aim of assessing their suitability for beer production. A multivariate analysis approach to experimental data showed a high content of α- and β-acids and myrcene in the Centennial, Brewer's Gold, Sterling, Cascade, Nugget, and Columbus varieties; a consistently lower percentages of humulones and a predominance of sesquiterpene hydrocarbons in the cultivars Mount Hood, Northern Brewer, Northdown, Galena, Willamette, and Fuggle; and a desirable high α-acids content and a sesquiterpene-type aroma in cultivars Chinook, Yeoman, and Hallertau. Further studies are needed to assess the environmental adaptability and the yield performance of hop plants in the pedoclimatic conditions of the Central Italy hills
Comparison between fatty acid profiles of old and modern varieties of T. turgidum and T. aestivum : A case study in central Italy
No full textOld and modern tetraploid (Triticum turgidum ssp. durum and Triticum turgidum ssp. turanicum) and hexaploid (Triticum aestivum ssp. aestivum) varieties collected in the Marche region (Central Italy) were compared for fatty acid profile of whole grain flour through linear discriminant analysis. Two independent trials were carried out in 2015 and 2016: the first analyzed grain samples collected from organic farmers (old varieties) or wheat storage facilities (modern varieties), the second using grain produced by an experimental field trial, aimed to compare old and modern varieties under identical agronomic and environmental conditions. Multivariate analysis demonstrated that both the most and the least represented fatty acids provided an effective discrimination not only between the main groups (turgidum vs aestivum) but also between old and modern varieties within each main group of wheats. Four fatty acids (arachidic, oleic, vaccenic and linolenic) were included in discriminant analysis models of both 2015 and 2016 data sets. Results were consistent between the two years of trial suggesting that the cultivation system (organic or conventional) could influence but did not prevent the discrimination between the old and modern varieties, since the same trend in classification was observed for both tetraploid and hexaploid groups of varieties
Characterization of lipid substances of rose hip seeds as a potential source of functional components: A review
Full text linkFunctional foods receive the greatest attention for nutritional needs of specific consumers. The rose hip fruit, besides carotenoids and polyphenols, are also good sources of lipid substances (fatty acids, sterols and tocopherols), which can be used as functional foods instead of being discarded as waste. The aim of this review is to present an overview of the lipid characterization of rosehip seeds as affected also by the oil extraction procedure. The rosehip seeds oil is proven to be rich in polyunsaturated fatty acid (PUFA), sterols and tocopherols, which provide specific biological activities (anti-inflammatory, anti-obesity, antioxidant, anti-diabetic activity). In particular, the oil content of rose hip seeds ranges from 5 to 18 % and is composed of unsaturated fatty acids such as linoleic acid (36-55 %) which is the most abundant one, linolenic (17-27 %) and oleic acid (15-22 %) respectively. As for the sterols, its content ranges around 5 g/kg constituting predominantly βSitosterol, whereas, the tocopherols amount to around 1 g/kg with γ-tocopherol being the most abundant
First ATR-FTIR Characterization of Black, Green and White Teas (Camellia sinensis) from European Tea Gardens: A PCA Analysis to Differentiate Leaves from the In-Cup Infusion
Full text linkATR-FTIR (Attenuated Total Reflectance Fourier Transform InfraRed) spectroscopy, combined with chemometric, represents a rapid and reliable approach to obtain information about the macromolecular composition of food and plant materials. With a single measurement, the chemical fingerprint of the analyzed sample is rapidly obtained. Hence, this technique was used for investigating 13 differently processed tea leaves (green, black and white) all grown and processed in European tea gardens, and their vacuum-dried tea brews, prepared using both hot and cold water, to observe how the components differ from tea leaf to the in-cup infusion. Spectra were collected in the 1800–600 cm−1 region and were submitted to Principal Component Analysis (PCA). The comparison of the spectral profiles of leaves and hot and cold infusions of tea from the same country, emphasizes how they differ in relation to the different spectral regions. Differences were also noted among the different countries. Furthermore, the changes observed (e.g., at ~1340 cm−1) due to catechin content, confirm the antioxidant properties of these teas. Overall, this experimental approach could be relevant for rapid analysis of various tea types and could pave the way for the industrial discrimination of teas and of their health properties without the need of time-consuming, lab chemical assays
Assessment of lipid oxidation in fish and fish products processed by cold plasma technologies
Full text linkPlasmas generated at or near ambient temperature are emerging as mild, selective and environmentally friendly technologies for extending the shelf-life of perishable fish and fish products. However, the high degree of unsaturation makes fish lipids highly susceptible to the reactive oxygen and nitrogen species (RONS) of plasmas, which can trigger the onset and/or progression of lipid oxidation, leading to the formation of off-flavours, the loss of nutritionally valuable components (polyunsaturated fatty acids, proteins, vitamins) and the formation of risky or toxic substances. Despite numerous experiments on the decontamination effects of cold plasma on fish and fish products, the evaluation of lipid oxidation has been limited to a few parameters. Most studies have focused on measuring global indices of primary and secondary oxidation products (peroxide value and thiobarbituric acid reactive substances, respectively) and some researchers have analysed total fatty acid composition as an indirect measure of the degree of oxidation. However, more advanced analytical methods for the direct quantification of volatile and non-volatile chemical species derived from the oxidation of fatty acids and sterols have been performed only to a very limited extent. The results on the effects of cold plasma on lipid oxidation in fish and fish products are contradictory. Although several studies show a pro-oxidant effect of RONS, others report no significant effects on lipid oxidation and even a lower rate of lipid oxidation during storage of fish products
Discrimination among varieties of Triticum turgidum subspecies (dicoccon, turanicum and durum) based on the fatty acid profile
No full textFatty acid (FA) profiles of one dicoccon (emmer), two turanicum and seven durum varieties of Triticum turgidum, including two old durum varieties (Senatore Cappelli and Taganrog), were evaluated at two different sowing seasons in a split-plot design. Univariate (Analysis of Variance, ANOVA) and multivariate (Linear Discriminant Analysis, LDA) were applied. Univariate analysis discriminated the emmer wheat variety due to its high oleic, arachidic and eicosenoic acids and low linoleic and linolenic acids. The n-6/n-3 ratio discriminated the three subspecies (dicoccon vs turanicum vs durum). LDA allowed to further discriminate all varieties among each other. In particular, the old durum Senatore Cappelli was clearly discriminated from modern ones, whereas Taganrog was closer to them. Nutritional parameters confirmed the high quality of fatty acid profile of all varieties due to the prevalence of unsaturated fatty acids, but the high n-6/n-3 ratio suggested that these cereals must be included in diets enriched of n-3 fatty acids. Variety ' Sowing Season interaction was detected mainly by LDA approach. Overall, univariate and LDA supplied complementary information on variability of fatty acid contents among and within T. turgidum subspecies
Impact of different stoppers on the composition of red and rosé lagrein, schiava (vernatsch) and merlot wines stored in bottle
No full textDifferent technical cork stoppers (blend of natural cork microgranules, one-piece natural cork, agglomerated natural cork, technical cork 1+1) were compared to evaluate the effects on the phenolic, volatile profiles and dissolved oxygen in three red (Merlot, Lagrein red, St. Magdalener) and one rosé (Lagrein rosé) wines, which were stored in bottles for 12 months. Gallic acid, caffeic acid, p-coumaric acid, trans-resveratrol, glutahionyl caftaric acid and protocatechuic acid did not vary remarkably during the first three months, whereas at six months a net increase was reported, followed by a clear decrease at 12 months. The same trend was observed in Lagrein rosé, but only for gallic acid. The total anthocyanins content decreased during the storage period in the four wines. Isopentyl acetate, 1-hexanol, ethyl hexanoate, 2-phenylethyl alcohol, diethyl succinate, ethyl octanoate and ethyl decanoate were the main volatile compounds. The sum of alcohols decreased in all four of the wines. The esters decreased in Merlot; however, they increased in Lagrein rosé, Lagrein red and St. Magdalener during the storage. Univariate and multivariate statistics and a sensory discriminant triangle test displayed similar influences of the different stoppers on the phenolic and volatile compounds during the whole storage duration. The changes detected in the phenolic and volatile concentrations were presumably due to the non-oxygen-mediated reactions occurring during 12 months of storage in bottle
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